This article mostly describes how to climb the mountain, focusing on the southern and western route. Some tour operators ask up to whopping 1000 euros for a three day trek to the summit. A guide is however absolutely unnecessary in summer and the trek is doable on your own without a problem. Open Street Maps has the four main routes embedded and the OsmAnd app with a GPS equipped phone is enough, even though not strictly necessary.
Mt. Damavand is part of the Alborz raneg in the north of Iran. Trekking and climbing damavand from may to October is very popular. There are skiing possibilities in winter in the area.
There are at least 16 trails up to the top of the mountain. The four main routes are the southern, the western, the northern and the northeastern routes. The last two are the longest. The western route is famous for its sunset views. The southern route is by far the most popular one.
For the southern and western routes, the first base camp is in the village of Polur, which is at some 2000 m above sea level and has some accommodation options. The "base camp" is the Iranian Mountaineers Association office, where foreigners pay a useless $50 climbing fee. This office is a few kilometers outside of the village, next to the road. At a sharp turn a little after the village there is a bad dirt road up a hill, which you can take if you have a bicycle or are on foot. This way you can avoid the office and thus paying the fee.
After Polur the paved road continues for about 10 km to a parking lot where the trail to the southern route starts. The first 7 km of this trail are on a dirt road which is doable by 4WD. For the western route you can properly organize a 4WD at the base camp. We "hitchhiked" there and payed 1,5 million Rial (1,5 hours) to the parking place (35,9586408, 52,0509931)
Polur is around 2 hrs away from Tehran by bus from the eastern bus terminal (TehranPars) (100,000 rial = $3). From Polur to the end of the paved road a taxi should cost around 20,000 toman ($6). Your hotel should be able to arrange a private car for you all the way to the end of the paved road for about 120,000 toman (25-30 euro). Tehran Hostel in Tehran certainly does that.
At the parking lot some taxi drivers will offer you a 4WD ride for the first 7 km to base camp 2 at 3000 m above sea level.
From camp 2 it is about 3 hrs uphill to camp 3, the last base camp at 4200 m. You can pay for your backpack to be carried by a donkey.
Passing the base camp without paying is no problem, but it might be difficult to organise a transport to the starting point. An option is to hitchhike to (35,8790634, 52,0444066) on paved road and then hike to the starting point. It might take you a whole day. Take enough water. On the way is only one source by some nomads tents (you can also ask them to take you up to the start), the next is near the hut (35,9564892, 52,0822861) at 4200m. At least it was like this in September.
Damavand town contains 37 historical tombs (Imamzadeh), 27 castle ruins, 23 traditional houses of architectural significance, 18 traditional bath houses, 6 caves, 5 historical bridges, 3 historical mosques, and 3 caravanserais.
The main landmarks are the Friday Mosque (15th century) and the Sheikh Shebli Mausoleum and Tower, dating to the Seljuq era.
Foreigners are supposed to pay a 50 dollar fee for climbing the mountain. This is sold outside of Polur at the Iranian Mountaineers Association. For the $50 you get a huge ticket with absolutely no information on it. There are no signs in English whatsoever on the trail and you need to pay extra for sleeping in the hut. Noone takes out the garbage either. You only get to use the toilets for free. Therefore it is not recommended to have bad conscience if you avoid paying the fee. If you arrive in a car with Iranian people and you don't say anything and look remotely Iranian, you will probably not be asked to pay. At the camps they sometimes ask if you paid the fee but rarely ask to see the ticket.
Camps 2 and 3 offer some canned food and dry soups at inflated prices. You can bring your own food and gas stove.
There is a water tap at both camps and not any permanent springs in the height of summer. It is best to drink bottled water which is sold in big bottles at both camps. (2000 toman at camp 2 and 4000 toman at camp 3). A small bottle of coke for 2000
Most people make it to camp 3 the first day and sleep there. There is a hut with a lot of space but it gets extremely crowded on weekends (Thursday and Friday) in the summer. If you bring your tent there is plenty of camping space. The toilets are very smelly and unfortunately the place is full of garbage.
Camp 2 at 3000 m also has camping space and you can also pay to sleep in the mosque or in some rooms attached to a smelly toilet. This camp is known as not very friendly and locals usually avoid sleeping there. There are a couple of flat spots to put your tent between the two camps but bring water if you wild camp like that.
There is one hut at 4200 m (35,9564892, 52,0822861) which is open and had no staff. As we did not pay the permit and where there alone we don't know if you normally have to pay. However there are plenty of good camping options outside as well. Take care of the shepherd. One (most probably) stole our sleeping bags. Fortunately we hid our backpacks behind some rocks. We were there alone and he came by the day earlier. Probably to check the place out.
Peak day is challenging. It took us 7h up, 1h on top and 2h down to the hut. Especially the last 200m are more difficult, so you should have some experience. We lost the path a bit and had to climb sometimes (nothing difficult, but unexpected)
Mt Damavand is at extreme altitude. Good acclimatization is very important. It is recommended to spend two nights at camp 3 with an acclimatization walk to 5100 m during the "rest day".
There is a strong smell at sulfur at about 5300 m which some people find problematic.
The weather can turn nasty even in the height of summer with strong winds and extreme cold. Generally however you don't need special equipment to climb mt Damavand in summer (best July and August). In winter this should be attempted only by very experienced and well equipped mountaineers.
Take care of the shepherd on the western route. He most likely stole our sleeping bags. Hide your stuff outside during peak day, if you are there alone.
There is Irancell coverage to around 4500 m altitude on the southern route.
The way you came in. Try to get a ride with someone from camp 2 to Polur. Then flag down a bus or hitchhike to Tehran.
Organise someone to pick you up in advance (bad cellphone coverage), hike back the road and hope for a car to take you. Or cross to the south-west route (experience and good maps needed). Takes about 9h to the parking lot of the southern route.